Lord Griffiths:

My Lords,

The Court of Appeal has certified the following point of law of general public importance:

Whether a party seeking to rely on computer evidence can discharge the burden under s. 69(1)(b) of the Police and Criminal Evidence Act 1984 without calling a computer expert, and if so how?

The point of law falls to be considered against the following background of fact. The appellant was arrested at her home at Maple Cross, Rickmansworth at about 5.30 pm on 17 March 1989. In her car were goods from Marks & Spencers worth 24378.36. The goods consisted of various items of food, including a joint of beef priced at 24312.57 and five items of clothing. The appellant had no receipt. In an initial interview on 17 March 1989 she declined to answer questions. She was interviewed again on 29 April 1989 when she said that she had bought the goods at Marks & Spencers at St Alban's. When she returned to her car the bags had split so she transferred the shopping to a bag of her own. She said she never kept receipts and denied stealing the goods.

The principal evidence for the prosecution was given by a store detective employed by Marks & Spencers at their St Alban's branch. She said that at 10 am on the morning of 18 March she removed all the till rolls from the tills and recovered a further two till rolls from a cupboard which bore the date 17 March. She explained that the tills were connected to a central computer which fed in the date, time, customer number and till number on each of the till rolls.

She further explained that each item of clothing has upon it a seven figure numbered label known as a Unique Product Code or U.P.C. The U.P.C. numbers are unique to clothing of a particular type, size and colour. The till operator punches in the U.P.C. number on the till which then registers the appropriate price.

In the case of food each item of food has a price upon it and the operator punches in the price of each item on the till. She said that they had had no trouble with the operation of the central computer.

She carried out an examination of all the till rolls which she had recovered from the tills which would have been those in use on 17 March and stamped as such by the central computer and she also examined the two till rolls also stamped and dated 17 March which had been placed in the cupboard where all used till rolls were kept. She thus examined all the till rolls in use on 17 March.

She said that there was no trace on the till rolls of the U.P.C.s for the clothing found in the appellant's car. She said there was no record on any of the till rolls of an item of food costing 24312.57, the price of the beef. Nor was there any group of prices matching the items of food found in the car.

It was quite apparent from the store detective's evidence that she was thoroughly familiar with the operation of these tills and of the computer, albeit she did not pretend to any technical understanding of the operation of the computer.

The appellant did not herself give evidence and no evidence was called on her behalf. The jury convicted her. If the till rolls were properly admitted in evidence this is hardly surprising for they provided the most powerful evidence of guilt.

It is however submitted that the till rolls should not have been admitted in evidence because the store detective's evidence did not satisfy the provisions of s. 69 of the Police and Criminal Evidence Act 1984 which provides:

(1) In any proceedings, a statement in a document produced by a computer shall not be admissible as evidence of any fact stated therein unless it is shown -

(a) that there are no reasonable grounds for believing that the statement is inaccurate because of improper use of the computer;

(b) that at all material times the computer was operating properly, or if not, that any respect in which it was not operating properly or was out of operation was not such as to affect the production of the document or the accuracy of its